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1.
Nonlinear magnetotransport of two-dimensional electrons in modulation-doped GaAs/AlAs heterostructures with anisotropic mobility is investigated. The mobility attains its maximum and minimum values in the $\left[ {1\bar 10} \right]$ and [110] directions, respectively. It is found that, upon an increase in the direct electrical current I dc though Hall bars oriented along the [110] direction, the transition of the two-dimensional system to the state with differential resistance r xx ≈ 0 in a magnetic field occurs at a lower value of I dc and is accompanied by a more pronounced “plunge” into the region of negative r xx values as compared to bars oriented along the $\left[ {1\bar 10} \right]$ direction. The results are explained by the impact of mobility on the spectral diffusion of nonequilibrium charge carriers. 相似文献
2.
M. A. Murzinova S. V. Zherebtsov G. A. Salishchev 《Journal of Experimental and Theoretical Physics》2016,122(4):705-715
The specific energy of interphase boundaries is an important characteristic of multiphase alloys, because it determines in many respects their microstructural stability and properties during processing and exploitation. We analyze variation of the specific energy of the β/α interface in the VT6 titanium alloy at temperatures from 600 to 975°C. Analysis is based on the model of a ledge interphase boundary and the method for computation of its energy developed by van der Merwe and Shiflet [33, 34]. Calculations use the available results of measurements of the lattice parameters of phases in the indicated temperature interval and their chemical composition. In addition, we take into account the experimental data and the results of simulation of the effect of temperature and phase composition on the elastic moduli of the α and β phases in titanium alloys. It is shown that when the temperature decreases from 975 to 600°C, the specific energy of the β/α interface increases from 0.15 to 0.24 J/m2. The main contribution to the interfacial energy (about 85%) comes from edge dislocations accommodating the misfit in direction [0001]α || [110]β. The energy associated with the accommodation of the misfit in directions \({\left[ {\bar 2110} \right]_\alpha }\left\| {{{\left[ {1\bar 11} \right]}_\beta }} \right.\) and \({\left[ {0\bar 110} \right]_\alpha }\left\| {{{\left[ {\bar 112} \right]}_\beta }} \right.\) due to the formation of “ledges” and tilt misfit dislocations is low and increases slightly upon cooling. 相似文献
3.
Zhi Yang Xing-Gang Wu Li-Cheng Deng Jia-Wei Zhang Gu Chen 《The European Physical Journal C - Particles and Fields》2011,71(3):1563
In Deng et al. (Eur. Phys. J. C 70:113, 2010), we have dealt with the production of the two color-singlet S-wave (c[`(b)])(c\bar{b})-quarkonium states Bc(|(c[`(b)])1[1S0]?)B_{c}(|(c\bar {b})_{\mathbf{1}}[^{1}S_{0}]\rangle) and B*c(|(c[`(b)])1[3S1]?)B^{*}_{c}(|(c\bar{b})_{\mathbf{1}}[^{3}S_{1}]\rangle) through the Z
0 boson decays. As an important sequential work, we make a further discussion on the production of the more complicated P-wave excited (c[`(b)])(c\bar{b})-quarkonium states, i.e. |(c[`(b)])1[1P1]?|(c\bar{b})_{\mathbf{1}}[^{1}P_{1}]\rangle and |(c[`(b)])1[3PJ]?|(c\bar{b})_{\mathbf{1}}[^{3}P_{J}]\rangle (with J=(1,2,3)). More over, we also calculate the channel with the two color-octet quarkonium states |(c[`(b)])8[1S0]g?|(c\bar{b})_{\mathbf{8}}[^{1}S_{0}]g\rangle and |(c[`(b)])8[3S1]g?|(c\bar{b})_{\mathbf{8}}[^{3}S_{1}]g\rangle, whose contributions to the decay width maybe at the same order of magnitude as that of the color-singlet P-wave states according to the naive nonrelativistic quantum chromodynamics scaling rules. The P-wave states shall provide sizable contributions to the B
c
production, whose decay width is about 20% of the total decay width
\varGamma Z0? Bc\varGamma _{Z^{0}\to B_{c}}. After summing up all the mentioned (c[`(b)])(c\bar {b})-quarkonium states’ contributions, we obtain
\varGamma Z0? Bc=235.9+352.8-122.0\varGamma _{Z^{0}\to B_{c}}=235.9^{+352.8}_{-122.0} KeV, where the errors are caused by the main sources of uncertainty. 相似文献
4.
Physics of the Solid State - In accordance with the orientation ratio (110), [001]β || (111), [$$1\bar {1}0$$]α established by fast electron diffraction between the ordered (β) and... 相似文献
5.
Chong-Xing Yue Wei Wang Zheng-Jun Zong Feng Zhang 《The European Physical Journal C - Particles and Fields》2005,42(3):331-339
In the framework of the littlest Higgs (LH) model, we consider the processes
and
, and we calculate the contributions of new particles to the cross sections of these processes in the future high energy e + e- collider (ILC) with
TeV. We find that, with reasonable values of the free parameters, the deviations of the cross sections for the processes
from their SM values might be comparable to the future ILC measurement precision. The contributions of the light Higgs boson H0 to the process
are significantly large in all of the parameter space preferred by the electroweak precision data, which might be detected in the future ILC experiments. However, the contributions of the new gauge bosons BH and ZH to this process are very small.Received: 22 February 2005, Revised: 27 April 2005, Published online: 6 July 2005PACS:
12.60.Cn, 14.70.Pw, 14.80.Cp 相似文献
6.
A Fe+5.07 at.%Si single crystal has been studied by ultrasonic-pulse technique. Its density and elastic constants were determined
for p=0 and T=293 K. The dependence of the elastic properties of silicious iron on Si concentration was constructed. The compression, the
effective elastic constants, and the Grüneisen parameters were measured at hydrostatic pressures of up to 9 GPa. It was found
that for p=0,
and
. The elastic constants c
44 and c′ increase linearly with pressure by 19.3 and 18.2% by p=9 GPa. The elastic anisotropy does not vary with pressure. For p>4 GPa, c
11, c
12, and K
S were observed to increase nonlinearly with decreasing pressure derivative. The Grüneisen parameter γ
LA decreases with pressure down to 0.70 at 9 GPa to become negative when extrapolated to the region of the α−ɛ phase transformation. The anomalies in c
11 and the negative values of γ
LA for p>11 GPa indicate that the phase transformation in silicious iron at 13.5 GPa can take place by the crystallographic mechanism
of the α−ɛ transformation in pure iron, i.e. by lattice compression in the [001] direction and shearing of the (110) planes along
or
. An assumption is put forward that pressure gives rise in silicious iron to sp-d hybridization, which results in increased screening of the ion-ion interaction and in anomalies in elastic properties. Similar
phenomena are expected to occur in pure bcc Fe as well.
Fiz. Tverd. Tela (St. Petersburg) 41, 516–522 (March 1999) 相似文献
7.
A novel micro accelerometer with adjustable sensitivity based on resonant tunneling diodes 下载免费PDF全文
Resonant tunnelling diodes (RTDs) have negative differential
resistance effect, and the current--voltage characteristics change
as a function of external stress, which is regarded as
meso-piezoresistance effect of RTDs. In this paper, a novel micro-accelerometer based on AlAs/GaAs/In0.1Ga0.9As/GaAs/AlAs
RTDs is designed and fabricated to be a four-beam-mass structure,
and an RTD-Wheatstone bridge measurement system is established to
test the basic properties of this novel accelerometer. According to
the experimental results, the sensitivity of the RTD based micro-accelerometer is adjustable within a range of 3 orders when the bias
voltage of the sensor changes. The largest sensitivity of this RTD
based micro-accelerometer is 560.2025 mV/g which is about 10 times
larger than that of silicon based micro piezoresistive
accelerometer, while the smallest one is 1.49135 mV/g. 相似文献
8.
A. G. Grozin 《Zeitschrift fur Physik C Particles and Fields》1987,34(4):531-544
The cross section of isolated nucleon production with large transverse momentum in nucleonnucleon collisions is calculated. This process is due to the hard scatteringqq→B q. A general selection rule for helicity amplitudes of the processes involving mesons and baryons is established. In particular it leads to the vanishing of the amplitudesq + q + \( \to B_{ + 3/2} \bar q - ; \gamma _ + \gamma _ + \to M_{ + 1} M_{ - 1} ,B_{ + 3/2} \bar B_{ - 3/2} \) . The quantitative estimates using the nucleon wave function from [5] show that the selection of the events with isolated proton production is possible in ISR data. 相似文献
9.
As was shown in the first part of this study [1], slip occurs in polycrystalline ordered Mg3Cd, which has a DO19 superstructure, along the {0001} basis planes, {1010} prismatic planes, and {1011} and {1012} pyramidal planes [2,3]. The formation of segregations at antiphase boundaries (APB's) in the {0001} basis and {1011} pyramidal planes was also examined there [1]. Segregations at APB's in
planes are treated in this second part of the study. A zero-energy APB may form in the
prismatic plane [4]. Segregation of atoms, on the other hand, is not allowed at such an APB according to the Gorskii-Bragg-Williams theory if correlation and interaction in the second and higher coordination spheres are not taken into account.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, Vol. 12, No. 5, pp. 62–70, May, 1969.The authors thank N. S. Golosov and N. V. Kozhemyakin for discussion of this study and valuable advice. 相似文献
10.
Formation of ultrafine and dense α-Al2O3 nanoparticles via kinetic phase change in a dynamic process
Ultrafine (5 nm) Al2O3 nanoparticles having a predominant α-type structure and with an internal compressive stress up to ca. 15 GPa were synthesized by pulsed laser ablation on Al target under a very high power density (1.8 × 1012 W/cm2) with oxygen flow in vacuum. The ultrafine α-Al2O3 was alternatively formed from the minor γ-Al2O3 nanocondensates upon electron irradiation. In such a case, the polymorphs follow a special crystallographic relationship [110]γ//[2 $ \bar{1}$ $ \bar{1} $ 0]α; ( $ \bar{1} $ 1 $ \bar{1} $ )γ//(0 $ \bar{1} $ 14)α with a mixed mismatch strain yet nonparallel close-packed planes indicating a reconstructive-type transformation. The formation of metastable α-Al2O3 in the dynamic processes can be rationalized by the kinetic phase change from the amorphous lamellar and/or γ-Al2O3 depending on their free energy versus cell volume curves. The dense and ultrafine-sized Al2O3 polymorphs with a rather low minimum band gap of 3.7 eV shed light on their natural occurrence in dynamic settings and abrasive as well as catalytic/optoelectronic applications. 相似文献
11.
Longhai Shen Xuefei Li Qiliang Cui Bingbing Liu Tian Cui 《Applied Physics A: Materials Science & Processing》2010,99(1):111-115
Single-crystal ripple-like AlN nanowire with tuned diameter was fabricated through direct reaction aluminum with nitrogen
by arc discharge method. The nanowires grow along the [0001] direction and have a radial expansion along the
[10[`1]0][10\bar{1}0]
direction. The periodic variation of the radial expansion toward
[10[`1]0][10\bar{1}0]
direction produces the ripple-like AlN nanowires. The growth mechanism of the AlN nanowires is discussed by considering the
Al adlayer diffusion on the polar (0001) surface. 相似文献
12.
The decay chain
is identified in a sample of 3.9 million hadronic Z decays collected with the OPAL detector at LEP. The branching ratio BR
is measured to be
for the J
P
=1+ (D0
1) state. For decays into the J
P
=2+ (D2
*0) state, an upper limit of 1.4 x 10-3 is placed on the branching ratio at the 95% confidence level.Received: 20 December 2002, Revised: 15 April 2003, Published online: 12 September 2003 相似文献
13.
14.
M. B. Ivanov S. S. Manokhin D. A. Nechaenko Yu. R. Kolobov 《Russian Physics Journal》2011,54(7):749-755
Investigations of disperse nonmetallic inclusions in unalloyed alpha titanium VT1-0 have been performed by using transmission
electron (including scanning and high-resolution) microscopy. Characteristic electron energy losses spectroscopy has shown
that these inclusions are titanium carbide particles. It has been revealed that the disperse carbides are formed in the titanium
hcp matrix as a phase based on the fcc sublattice of titanium atoms. The inclusion–matrix orientation relationship corresponds
to the well-known Kurdyumov–Sachs and Nishiyama–Wassermann relationships
[ 2[`11] 0 ]\upalpha ||[ 011 ]\updelta \text and ( 000[`1] )\upalpha ||( 1[`1] 1 )\updelta {\left[ {2\overline {11} 0} \right]_{{\upalpha }}}\parallel {\left[ {011} \right]_{{\updelta }}}{\text{ and }}{\left( {000\overline 1 } \right)_{{\upalpha }}}\parallel {\left( {1\overline 1 1} \right)_{{\updelta }}} . 相似文献
15.
First-principles investigation of BAs and BxGa1-xAs alloys Using first-principles calculations in the generalized gradient approximation, the electronic properties of BAs and BxGa1-xAs alloys are studied. At the Brillouin-zone centre, the lowest conduction band is the three-degenerate p-like Г15c state rather than s-like Г1c state, and the conduction band minimum (CBM) is along the A line between the Г and X points-at approximately 11/14(1,0,0)2π/a. With boron content at 0%-18.75%, BxGa1-xAs alloys have a small (2.6 eV) and relatively composition-independent band-gap bowing parameter, the band-gap increases monotonically by -18meV/B% with increasing boron content. In addition, the formation enthalpies of mixing for BxGa1-xAs alloys with boron content at 6.25% and 12.5% are calculated, and the large formation enthalpies may explain the difficulty in alloying boron to GaAs. 相似文献
16.
The distinction between avalanche and tunneling breakdown in one-sided abrupt junctions is made on the basis of a new, simple expression for the tunneling breakdown field strengthF t. It is shown thatF t [V/cm] depends upon the temperatureT [K], the reduced tunneling effective massm eff + /m o and the semiconductor energy band gapE g [eV] according to the following equation $$F_t = 1.76 \cdot 10^6 \cdot \left( {\frac{T}{{300}}} \right) \cdot \left( {\frac{{m_{eff}^ + }}{{m_0 }} \cdot E_g } \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} [V/cm].$$ Using published calculations for the avalanche breakdown voltage, the result is applied to the semiconductors Ge, Si, GaAs and GaP at 300 K and InSb at 77K. 相似文献
17.
The very recently observed D*sJ(2463) meson is described as a
bound state in a unitarised meson model, owing its existence to the strong OZI-allowed
coupling to the nearby S-wave
threshold. By the same non-perturbative mechanism, the narrow axial-vector Ds1(2536) resonance shows up as a quasi-bound-state partner embedded in the
continuum. With the same model and parameters, it is also shown that the preliminary broad 1 + D1(2400) resonance and the established narrow 1 + D1(2420) may be similar
partners, as a result of the strong OZI-allowed
coupling to the nearby S-wave
threshold. The continuum bound states D1(2420) and Ds1(2536) are found to be mixtures of 33%
and 67%
, whereas their partners D1(2400) and D*sJ(2463) have more or less the opposite
-state content, but additionally with some
or
admixture, respectively. The employed mechanism also reproduces the ratio of the KL-KS mass difference and the KS width, by describing KL as a bound state embedded in the
continuum. The models results for
states containing one b quark are also discussed.Received: 7 June 2003, Revised: 20 October 2003, Published online: 18 December 2003PACS:
12.40.Yx, 14.40.Aq, 14.40.Lb, 13.25.Es, 13.25.Ft, 13.75.Lb 相似文献
18.
Moritz Trautvetter Ulf Wiedwald Heiko Paul Alexander Minkow Paul Ziemann 《Applied Physics A: Materials Science & Processing》2011,102(3):725-730
Solid-phase epitaxy is demonstrated for the metallic binary alloy AlFe. Stoichiometric thin films are deposited at ambient
temperature onto c-cut sapphire by pulsed laser deposition (PLD), resulting in smooth amorphous films as revealed by X-ray diffraction (XRD)
and atomic force microscopy (AFM). By annealing at 600°C, still smooth epitaxial AlFe films are obtained exhibiting the B2
phase with the (110) direction parallel to the substrate normal and an in-plane orientation as given by AlFe[001]||Al2O3[11[`2]0]\mbox{AlFe}[001]\|\mbox{Al}_{2}\mbox{O}_{3}[11\bar{2}0]. While ferromagnetism is observed for the amorphous phase, the formation of the B2 structure is accompanied by paramagnetic
behavior, confirming the high structural quality. 相似文献
19.
Hua Li Jianping Sang Chang Liu Hongbing Lu Juncheng Cao 《Central European Journal of Physics》2008,6(3):638-642
Single crystalline ZnO film is grown on GaN/sapphire (0001) substrate by molecular beam epitaxy. Ga2O3 is introduced into the ZnO/GaN heterostructure intentionally by oxygen-plasma pre-exposure on the GaN surface prior to ZnO
growth. The crystalline orientation and interfacial microstructure are characterized by X-ray diffraction and transmission
electron microscopy. X-ray diffraction analysis shows strong c-axis preferred orientation of the ZnO film. Cross-sectional
transmission electron microscope images reveal that an additional phase is formed at the interface of ZnO/GaN. Through a comparison
of diffraction patterns, we confirm that the interface layer is monoclinic Ga2O3 and the main epitaxial relationship should be and .
相似文献
20.
The effect of microwave radiation on magnetotransport in single GaAs quantum wells with anisotropic mobility, whose maximum
corresponds to the
direction and minimum to the [110] direction, is investigated using the Van der Pauw method. In samples shaped as squares
with sides oriented along the
and [110] directions, giant oscillations of magnetoresistance arise under the effect of a microwave field for the both
and [110] orientations of the measuring current I
ac. In the anisotropic two-dimensional system under study, the relative amplitude of microwave photoresistance oscillations
in a magnetic field weakly depends on the orientation of I
ac. At a temperature of 4.2 K and a microwave frequency of 130 GHz, magnetic field intervals characterized by close-to-zero
resistance manifest themselves only for the case of the [110] orientation of I
ac. The aforementioned experimental results are qualitatively explained by a quasi-one-dimensional potential modulation of the
two-dimensional electron gas in the [110] direction.
Original Russian Text ? A.A. Bykov, D.R. Islamov, A.V. Goran, A.K. Bakarov, 2007, published in Pis’ma v Zhurnal éksperimental’noĭ
i Teoreticheskoĭ Fiziki, 2007, Vol. 86, No. 12, pp. 891–895. 相似文献